NIDA Small Grant: This small grant application meets the funding priority: 1. Newer, less experienced investigator (PI). The applicant is in the end of the fourth year of a K08 entitled Drug Abuse, Pubertal Hormones, and AD/HD in Adolescence. This study will extend her work in the area of psychopharmacologic research in drug abuse in youth with Attention Deficit/Hyperactivity Disorder (AD/HD). This Phase 1 clinical trial will examine the safety and efficacy of modafinil and nicotine, alone and in combination, on abstinence-induced nicotine withdrawal in nicotine-dependent adolescents. Physiological, behavioral and subjective measures of impulsivity/inattention and depressive symptoms and other measures of nicotine withdrawal will be assessed in nicotine-dependent adolescents (16-18 years) who smoke 10 or more cigarettes per day and who started smoking before age 15. This study is based on the observations that impulsivity/inattention and depressive symptoms are associated with nicotine use, onset, dependence, withdrawal, cessation, and direct effects. Modafinil is a promising pharmacologic agent for the modification of symptoms of impulsivity/inattention and depression and is purported to have low abuse potential. It is hypothesized that modafinil will selectively diminish withdrawal-induced increases in impulsivity and depressive symptoms and offset reductions in attention, and the magnitude of these effects will be greater than those seen with nicotine replacement. In addition, it is hypothesized that the combination of modafinil and nicotine replacement will have a greater effect on nicotine withdrawal symptoms, particularly the withdrawal symptoms related to impulsivity/inattention and depression than either drug alone. This study will provide pilot data for an R01 submission that will investigate whether modafinil might be useful in the prevention of nicotine use and in a comprehensive behavioral and pharmacologic treatment intervention for early onset adolescent nicotine users.